In various industrial fields including chemical industry, electric power industry, and steel industry, a ceramic honeycomb structure excellent in heat resistance and corrosion resistance is adopted as a carrier or a filter for a catalytic device used for, for example, environmental protection and the recovery of specific materials. In recent years in particular, a honeycomb structure is actively used for a diesel particulate filter (DPF) to trap particulate matters (PM) discharged from a diesel engine or the like as a plugged honeycomb structure formed by alternately plugging the open frontal areas on both end faces of cells.
As such a DPF, a honeycomb structure formed so that, in a cross section perpendicular to the center axis, the area of first cells having one ends (the ends on the exhaust gas inlet side) opened and the other ends plugged may be larger than the area of second cells having one ends (the ends on the exhaust gas inlet side) plugged and the other ends opened in order to inhibit the clogging caused by particulate matters and increase the quantity of trapped particulate matters by increasing the surface area of the cells into which an exhaust gas flows is disclosed (refer to Patent Documents 1 and 2 for example).    [Patent Document 1] JP-A-2004-896    [Patent Document 2] JP-A-56-124418